Vehicle door lock with improved anti-theft features

ABSTRACT

A vehicle door lock assembly has a latch ( 12 ) for mounting on a vehicle door. The latch ( 12 ) has at least one release lever for effecting releasing of the latch and at least one locking lever ( 14 ) for locking the latch, disabling the release lever, and unlocking the latch, enabling the release lever. A compound linkage ( 20, 24; 20, 124 ) operatively engages the locking lever ( 14 ). A lock cylinder ( 30, 130 ) has a spindle ( 28 ) which engages the linkage. The spindle ( 28 ) rotates in response to keyed rotation of a matched key being received by the lock cylinder ( 30; 130 ) which drives the linkage ( 20, 24; 20, 124 ) to effect movement of the locking lever ( 14 ). The spindle ( 28 ) is axially slidable to disengage the spindle from the linkage. A hollow shield ( 34 ) shrouds the locking lever ( 14 ), the linkage ( 20, 24; 20, 124 ) and the engagement between the linkage and the spindle ( 28 ), preventing access thereto. If the spindle is removed, the linkage will pivot away preventing manipulation thereof. The hollow shield ( 34 ) also separates the linkage ( 20, 24; 20, 124 ) from the lock cylinder opening further minimizing unauthorized manipulation of the locking lever.

This application claims priority to provisional No. 60/094,528, filedJul. 29, 1998.

FIELD OF INVENTION

This invention relates to a vehicle door lock having improved anti-theftfeatures. In particular, this invention relates to a vehicle door lockhaving a shield for protecting the lock from being unlocked by meansother than a key and a drop-off linkage between the key cylinder and theconnecting rod.

BACKGROUND OF THE INVENTION

Vehicle door latch systems are well known in the art. Typically, avehicle door will have a latch for engaging and cinching onto a striker.The door will have an inside handle and an outside handle for releasingthe latch and opening the door. Additionally, the door will have a lockfor preventing the door from being opened by either the inside handle orthe outside handle or both. For selected doors, the door is providedwith a key cylinder for locking and unlocking the doors.

Optionally, vehicles can be provided with a power lock and unlockoption. Each door latch is provided with an electric actuator forlocking and unlocking the door latches. The actuators are electricallyconnected to a common station for effecting selected and gangedoperation of the locks. The common station is now usually provided witha receiver which responds to a transmitter for remotely locking andunlocking the doors.

Additionally, rear doors are commonly provided with a lever fordisabling the inside door handle for child proofing the vehicle.

Notwithstanding the ability to lock or disable the doors of the vehicle,the vehicle is still susceptible to theft by the use of a tool known asa “slim-jim”. The “slim-jim” tool is inserted between the window and thewindow seal to manipulate the connecting rods between the locking leveror the release handle and the door latch. The “slim-jim” tool willeither unlock or open the door allowing the thief access to the vehicle,usually in less than 30 seconds.

SUMMARY OF THE INVENTION

The disadvantages of the prior art may be overcome by providing avehicle door latch with a shield extending between the latch and a keycylinder and providing a drop-off linkage between the key cylinder andthe connecting rod such that the shield protects against directmanipulation and the drop-off linkage protects against key cylindertampering.

According to one aspect of the invention, there is provided a vehicledoor lock assembly which includes a latch for mounting on a vehicledoor. The latch has at least one release lever for effecting releasingof the latch and at least one locking lever for locking the latch,disabling the release lever, and unlocking the latch, enabling therelease lever. A compound linkage operatively engages the locking lever.A lock cylinder has a spindle which engages the linkage. The spindlerotates in response to keyed rotation of a matched key being received bythe lock cylinder which drives the linkage to effect movement of thelocking lever. The spindle is axially slidable to disengage the spindlefrom the linkage. A hollow shield shrouds the locking lever, linkage andthe engagement between the linkage and the spindle, preventing accessthereto. If the spindle is removed, the linkage will pivot awaypreventing manipulation thereof.

DESCRIPTION OF THE DRAWINGS

In drawings which illustrate an embodiment of the invention,

FIG. 1 is a perspective view of the vehicle door lock with improvedanti-theft features of the present invention;

FIG. 2 is a top plan sectional view of the shield of FIG. 1;

FIG. 3 is a top plan sectional view of the shield of FIG. 1 with thelock cylinder removed;

FIG. 4 is a perspective view of the upper end of the shield of FIG. 1;

FIG. 5 is a perspective view of the upper end of the shield of FIG. 1with lock cylinder removed;

FIG. 6 is an end elevational view of a free rotation lock cylinder ofthe present invention, with key in;

FIG. 7 is an end elevational view of a free rotation lock cylinder ofthe present invention, with key out;

FIG. 8 is a partial perspective view of a second embodiment of a vehicledoor lock with improved anti-theft features of the present invention;

FIG. 9 is a sectional top plan view of the shield of FIG. 8;

FIG. 10 is a partial perspective view of a third embodiment of a vehicledoor lock with improved anti-theft features of the present invention;and

FIG. 11 is a side sectional view of the shield of FIG. 10.

DESCRIPTION OF THE INVENTION

Referring to the drawings, the door latch 12 incorporating the presentinvention is of conventional design and manufacture, commerciallyavailable on production vehicles. The door latch 12 has an outsidelocking lever 14 in addition to the usual levers (not illustrated)operably connected to an inside locking lever and inside door handle andoutside door handle 18. Rod 16 connects the outside door handle 18 tothe latch 12.

The outside locking lever 14 is pivotally connected to a compoundlinkage comprising a lock actuation rod 20 and drop-off link 24. Lever14 has an aperture 22 for receiving the rod 16. Rod 16 extends upwardlyto a door handle region of the vehicle door. The upper end of rod 16 isconfigured to pivotally receive drop-off link 24.

Drop off link 24 has an aperture 26 at one end for receiving a spindle28 of the lock cylinder 30. Aperture 26 is sized and configured torotate with the spindle 28. In the illustrated embodiment, the end ofspindle 28 is square and aperture 26 is also square. It is readilyunderstood that other complementary shapes, including rectangles,splines or other polygons may also be used to provide a drivingengagement. Once the key cylinder is installed, the end of spindle 24provides a driving engagement for effecting the locking and unlocking ofthe latch 12.

The lock cylinder 30 is preferably of the type as illustrated in FIGS. 6and 7 which will freely rotate until a matched key 32 is inserted toproperly align the tumblers to provide a driving connection. However,other conventional key cylinders may also be used.

A hollow shield 34 extends from the door latch 12 to the key cylinder30. Hollow shield 34 has an longitudinal slot 36 for receiving a sideedge of the latch 12 such that locking lever 14 is fully shrouded by thehollow shield 34. The hollow shield 34 has a first chamber 38 whichmerges upwardly to a rectangular cross section and communicates with asecond chamber 40 through an access port 42. In the preferredembodiment, the cross section of the second chamber 40 is substantiallynarrower than the first chamber 38.

Preferably, shield 34 is a hydroformed part. Alternatively, the shield34 can be manufactured using other conventional techniques using twohalves and then joining the halves together.

The access port 42 preferably has a width slightly greater than thethickness of the drop-off link 24 and less than the width of the upperend of the rod 20 which is configured to pivotally receive the link 24.The access port 42 thus allows the link 24 to pivot and prevents the rod20 from entering the second chamber 40.

A bracket wraps about the shield 34 to secure the shield 34 to theinside of the door adjacent a door panel 35. The lower end of the shield34 is secured directly to the latch 12. Depending on the design of thelatch, suitable slots are provided in the shield 34 such that otheractuating levers for door handles and inside door locks can extendtherethrough. An end cap 44 closes the upper end of the shield 34 in africtional fit. Shield 34 has a formed end 37 to close the lower end ofthe shield.

In operation, the shield 34 fully protects the rod 20 from beingmanipulated directly by a “slim-jim” as all operational parts of thelocking mechanism are internal to the shield 34. If a thief forcefullyremoves the lock cylinder 30, the end of spindle 28 will be retracted,releasing the drop-off link 24. The drop-off link 24 will pivotdownwardly from the end of rod 20. The minimal width of the secondchamber 40 at the upper end of the shield 34 minimizes the ability ofthe thief to reach through the key aperture to grab and manipulate therod 20 or the drop-off link 24. Additionally, the length of the rod 20could be reduced with an attendant increase in length of the drop-offlink 24. The decreased rod length will result in the spindle connectingend of the drop-off link 24 to pivot away, further reducing thelikelihood that the thief could reach through the key aperture to graband manipulate the rod 20 or the drop-off link 24.

In trials using the present invention, a professional security expertwas unable to break into the vehicle in under 30 minutes. It is acceptedthat if a thief takes longer than 30 seconds to break into a vehicle,the thief would likely move onto another vehicle.

Referring now to FIGS. 8 and 9, a second embodiment of the presentinvention is illustrated. The second embodiment is further provided withan arcuate drop-off link 124. The access port 42 of the shield 34 isdefined in part by embossments 50, 52 extending inwardly from oppositesides of the narrowed section 40. The embossments 50, 52 close the gapintermediate the lock cylinder 30 and the rod 20 in the first chamber 38of the shield 34. The drop-off link extends arcuately under theembossments 50, 52. The embossments 50, 52 creates another barrier for awould-be thief.

Referring now to FIGS. 10 and 11, another embodiment of the presentinvention is illustrated. In this embodiment, the upper end 54 of theshield 34 is closed, preferably by some mechanical means to form aprismatic shape. A complementary fitting bracket 56 covers the upper end54. Flange 58 has an aperture for receiving a fastener to attach thebracket 56 and shield 34 to the door frame. Key cylinder 130 has aflange 60 at the inboard end thereof. The flange 60 is sandwichedbetween the bracket 56 and the shield 34 after installation. Bracket 56functions to support the shield 34 and also to retain the key cylinder130 to the shield 34, as well as cover the end of spindle 28 on theinboard side.

The inboard end of key cylinder 130 has a non-circular shoulder 62 whichfits into a complementary non-circular aperture 64 in the outboard wallof narrow section 40. The shoulder 62 and aperture 64 prevents rotationof the key cylinder 130, in the event of a rotation without a key usinga tool such as a screwdriver.

Bracket 56 adds protection against penetration to the upper end 54. Theprismatic shape of upper end 54 makes it difficult to drill into the topof the shield 34.

The above-described embodiments of the invention are intended to beexamples of the present invention and alterations and modifications maybe effected thereto, by those of skill in the art, without departingfrom the scope of the invention.

We claim:
 1. A vehicle door lock assembly comprising: a latch (12) formounting one a vehicle door, said latch having at least one releaselever for effecting releasing of said latch and at least one lockinglever (14) for locking the latch, disabling said release lever, andunlocking the latch, enabling said release lever, a compound linkage(20, 24) operatively engaging said locking lever (14), a lock cylinder(30) having a spindle (28) engaging said compound linkage, said spindlebeing rotatable in response to keyed rotation of a matched key receivedby said lock cylinder to drive said compound linkage to effect movementof said locking lever (14), and axially slidable to disengage saidspindle from said linkage, and a hollow shield (34) shrouding said atleast one locking lever (14), said compound linkage and said engagementbetween said compound linkage and said spindle, preventing accessthereto, characterized by said compound linkage comprising a link (24)and a rod (20) pivotally connected thereto, said link (24) engaging saidspindle (28), said link (24) pivots away from said spindle (28) to bespaced therefrom when said lock cylinder (30) is retracted from saidassembly, wherein said hollow shield (34) separates said rod (20) fromsaid lock cylinder (30) and has a first chamber (38) communicating witha second chamber (40) through an access port (42), said first chamber(38) housing said rod (20) and said link (24) extends through saidaccess port (42) from said first chamber (38) to said second chamber(40), said access port (42) sized to permit said pivotal movement ofsaid link (24) and to prevent said rod (20) from entering said secondchamber (40).
 2. An assembly as claimed in claim 1 wherein said hollowshield (34) has an opening at one end configured to receive and enclosea portion of the latch (12) from which said locking lever (14) extends,and has an aperture at an opposite end region for receiving said lockcylinder (30).
 3. An assembly as claimed in claim 2 wherein said lockcylinder (30) is fixedly retained to said hollow shield (34)substantially preventing forced rotation thereof.
 4. An assembly asclaimed in claim 3 wherein said access port (42) is defined byembossments extending inwardly from opposite sides of said hollow shield(34).
 5. An assembly as claimed in claim 4 wherein said hollow shield(34) is closed at an end opposite said one end.
 6. An assembly asclaimed in claim 4 wherein said hollow shield (34) is open at an endopposite said one end and said assembly further comprises a cap (44)closing said open end.
 7. An assembly as claimed in claim 5, whereinsaid closed end is a prismatic shape and a bracket (56) complimentary tothe prismatic shape positions said shield (34).
 8. An assembly asclaimed in claim 6 wherein said link (24) is arcuate.